Self collapsible blow moulded plastic thin-walled containers and a dispensing method using same

Abstract

A blow molded bottle (1): a) which is self-collapsible during its emptying; b) which comprises at least two transversal grooves and/or ribs (6.1), preferably located in the tubular body portion (6), equipped with collapse starters (6.2); c) wherein the mean wall thickness (Tmean) of the tubular body portion (6) is—in an increasing order of preference—less than or equal to 200; 180; 160; 150 μm; preferably comprised between 65 and 150; and more preferably comprised between 90 and 130 μm. The invention also discloses a method, a preform (100) and a mold for the manufacture of the aforementioned container by blow molding. The invention also discloses a method for bottling liquid into the bottles (1), a method for dispensing the liquid, a dispenser for implementing the method and a method for packing the thin-walled bottles, in view of storage and transportation.

Claims

1. A plastic thin-walled container having: a top part; a tubular body portion; and a bottom structure opposite to the top part; wherein a) said plastic thin-wall container is self-collapsible during emptying of said plastic thin-walled container, said plastic thin-walled container being configured to collapse when set upside down during emptying without any additional force; b) said plastic thin-walled container comprises at least two transversal grooves located in the tubular body portion, at least some of the transversal grooves being equipped with at least two collapse starters; c) a mean wall thickness of the tubular body portion is between 65 μm and 150 μm.

2. The plastic thin-walled container according to claim 1, wherein stretching ratios are: hoop stretch ratio: 4.0-6.5; axial stretch ratio: 2.8-5.0; and overall stretch ratio: 11.20-32.5.

3. The plastic thin-walled container according to claim 1, wherein said plastic thin-walled container is manufactured by a blow molding process.

4. The plastic thin-walled container according to claim 1, wherein said plastic thin-walled container is a bottle and that a top part thereof includes: a neck end; a neck support ring; a neck; and in that a shoulder joins the neck to the tubular body portion.

5. The plastic thin-walled container according to claim 1, having a volume of at least 2 liters.

6. The plastic thin-walled container according to claim 1, wherein collapse starters extend inwardly -recess- or outwardly -pin- with respect to a longitudinal axis of the plastic thin-walled container.

7. The plastic thin-walled container according to claim 1, wherein the transversal groove or rib has a shape in straight longitudinal section chosen from the group consisting of a U-shape; V-shape and combinations thereof.

8. The plastic thin-walled container according to claim 1, wherein the tubular body portion is cylindrical, polyhedral or comprises plane face(s) and curved face(s).

9. The plastic thin-walled container according to claim 1, wherein the plastic is chosen among polymers which exhibit strain hardening when the polymers are elongated.

10. The plastic thin-walled container according to claim 1, wherein said plastic thin-walled container includes at least one terminal retractable part, which is in at least one of the top part and a bottom structure of the plastic thin-walled container.

11. The plastic thin-walled container according to claim 10, wherein the terminal retractable part comprises at least one retractation starter.

12. A method for dispensing a liquid contained in the plastic thin-walled container according to claim 1, wherein: 1. said filled plastic thin-walled container is set up-side down on a dispenser comprise at least a valve for controlling the flowing of the liquid; 2. the valve for controlling the dispensing of the liquid is opened; 3. the liquid flows out and the plastic thin-walled container self collapses; 4. the valve for controlling the flowing of the liquid is closed to stop the flowing and the self-collapse; 5. the collapsed plastic thin-walled container is withdrawn of the dispenser and replaced by a filled plastic thin-walled container as soon as the collapsed plastic thin-walled container does not dispense liquid any longer.

13. The plastic thin-walled container according to claim 1, wherein at least some of the transversal grooves or ribs are equipped with at least 4 collapse starters.

14. The plastic thin-walled container according to claim 1, wherein at least some of the transversal grooves or ribs are equipped with between 4 and 8 collapse starters.

15. The plastic thin-walled container according to claim 1, wherein the mean wall thickness of the tubular body portion is comprised between 90 μm and 130 μm.

16. The plastic thin-walled container according to claim 2, wherein: the hoop stretch ratio is 4.2-6.0; the axial stretch ratio is 3.0-4.5; and the overall stretch ratio is 12.6-27.0.

17. The plastic thin-walled container according to claim 3, wherein said plastic thin-walled container is manufactured by an injection stretch blow molding process.

18. The plastic thin-walled container according to claim 5, wherein the volume is of at least 3 liters.

19. The plastic thin-walled container according to claim 5, wherein the volume is of at least 5 liters.

20. The plastic thin-walled container according to claim 5, wherein the volume is comprised in a range of 2-20 liters.

21. The plastic thin-walled container according to claim 5, wherein the volume is comprised in a range of 7.5-12.5 liters.

22. The plastic thin-walled container according to claim 8, wherein the tubular body portion comprises substantially plane face(s) linked by curved face(s).

23. The plastic thin-walled container according to claim 9, wherein the plastic is chosen among the polyesters.

24. The plastic thin-walled container according to claim 9, wherein the plastic is chosen among the aromatic polyesters.

25. The plastic thin-walled container according to claim 9, wherein the plastic is chosen in the group comprising: PolyEthylene Terephtalate (PET), PolyEthyleneNaphtalate(PEN), PolyEthylene Furanoate (PEF) and PolyPropylene Terephtalate (PPT).

26. The plastic thin-walled container according to claim 11, wherein the at least one retractation starter is at least one of a groove, a folding line and a rib.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This description is made in reference to the enclosed drawings wherein:

(2) FIG. 1A is a front view of an empty and non-capped thin-walled bottle according to the invention, the bottom of which is non-retracted;

(3) FIG. 1A′ is a view on a larger scale showing a detail in circle A′ of FIG. 1A;

(4) FIG. 1A″ is a view on a larger scale showing a view in longitudinal section of a detail in circle A″ of FIG. 1A;

(5) FIG. 1B is a perspective view from the bottom of the thin-walled bottle of FIG. 1A;

(6) FIG. 1C is a reduced scale-diagram showing the shape of the collapse starters of a groove of the thin-walled bottle according to the invention, as seen from above;

(7) FIG. 1D is a view that corresponds to FIG. 1C, but for a variant embodiment;

(8) FIG. 2 comprises a partial longitudinal section of an thin-walled bottle according to the invention, which is filled with water and capped as the bottle of FIG. 5C, which rests on a flat support, and the bottom of which is retracted;

(9) FIG. 3 is a graph showing the mean wall thickness T.sub.mean of the thin-walled bottle of the present embodiment made from the PET W170;

(10) FIG. 4 comprises a front view, with a partial longitudinal section, of a preform of a bottle according to the present embodiment.

(11) FIG. 5A shows a filled thin-walled bottle according to the present embodiment set upside down and connected to a dispenser.

(12) FIG. 5B shows an empty non-capped thin-walled bottle according to the present embodiment, and also shown on FIGS. 1A & 1B,

(13) FIG. 5C shows a filled with water and closed thin-walled bottle according to the present embodiment;

(14) FIGS. 5D to 5I show the thin-walled bottle of FIG. 5C set upside down and connected to a dispenser, in different successive stages of the emptying of the thin-walled bottle on the dispenser,

(15) FIG. 5J shows the collapsed and emptied thin-walled bottle removed from the dispenser.

(16) FIGS. 6A-6C shows respectively the stacking of the filled thin-walled bottles according to the present embodiment (6A), the pressurization of a stacked thin-walled bottles by retractation of the bottles' tops (6C), and a top view of a retracted bottle (6B).

(17) The thin-walled bottle shown on the enclosed drawings, especially FIGS. 1A-1B-2 is a biaxial stretched blowed molded thin-walled bottle (1), which has a general cylindrical shape and which is made of PET, without being limited to this specific substance, it being also possible to make the bottle out of a material that is simple or composite, multilayer or compound, such as PVC or a polyolefin or a polyester. This thin-walled bottle (1) has a large-sized (e.g 20 liters) and is notably intended to contain water and to be set upside down on dispenser unit for Home and Office Delivery (HOD) as shown on FIG. 5A.

(18) This thin-walled bottle (1) is composed, from the top to the base, of the following parts: a neck end (2), a neck support ring (3), a neck (4), a shoulder (5) joining comprising one retractation starter (5.sub.1), which is a rib in this example—see FIGS. 1A,2-, a tubular body portion (6) which is imprinted with several continuous transversal grooves (6.sub.1) and with several collapse/fold starters (6.sub.2) located in the grooves (6.sub.1), and an integral bottom structure (7) including: a terminal curved portion (8) an outwardly axially extended terminal retractable bulge (9) and at least one retractation starter (7.sub.1) which joins the terminal curved portion (8) to the bulge (9), and which is a groove in this example—see FIGS. 1A,1A″,1B-.

(19) In the thin-walled bottle (1) shown on the enclosed drawings, the neck end (2) is threaded to receive a screwed cap 2′ as shown on FIGS. 5C; 5J; 6A; 6B. In a variant, the cap 2′ can be a snap cap which is fitted by force on an adapted neck finish composed of a neck end (2) and of a neck support ring (3). Classically, the bottom of the screwed cap 2′ is linked to a tamper-proof ring which lies on the neck support ring (3) which separates the neck end (2) and the neck (4).

(20) The rib (5.sub.1) of the shoulder (5) which acts as a retractation starter of the top of the thin-walled bottle (1) is shown in detail on FIG. 2. Said rib (5.sub.1) behaves as a reinforcement which makes it possible the thrusting of the upper part of the shoulder (5) and of the neck end (2), when a downward force is applied on the neck end (2) and/or when a upward force is applied on the bottom (7) of the thin-walled bottle (1). The retractation of the upper part of the shoulder (5) together with the neck end (2) of a water-filled and stacked thin-walled bottle (1) according to the invention is shown on FIG. 6B.

(21) The width of the rib (5.sub.1) is, for instance, comprised between 1-30 mm, preferably between 7-20 mm, more preferably equal to circa 12 mm.

(22) The height of the rib (5.sub.1) is, for instance, comprised between 0.5-20 mm, preferably between 2-10 mm, more preferably equal to circa 6 mm.

(23) The tubular body portion (6) is imprinted with e.g. 9 transversal continuous grooves (6.sub.1), each of them comprising 4 or 6 collapse/fold starters (6.sub.2), which are angularly offset around the axis.

(24) In the embodiment shown on the enclosed figures, especially on FIG. 1A′, the grooves (6.sub.1) of the thin-walled bottle (1) have each a V-shaped cross-section, and more particularly two coplanar edges (58) and an intermediate portion between the two edges (58), said intermediate portion presenting an apex (56) inwardly shifted with respect to the two edges. These latter are two straight branches (58) of the V-shape connected via circular arcs 60 to the substantially cylindrical side wall of the thin-walled bottle (1). Each groove (6.sub.1) presents a width (w) measured between the two edges and a maximum height (h) measured between the edges and the apex. In this embodiment, each groove (6.sub.1) includes collapse (or fold) starters (6.sub.2) which are bosses angularly distributed uniformly about the longitudinal axis (64) of the bottle (1) and which project outwardly from the bottoms of the grooves (6.sub.1). Said grooves (6.sub.1) are of constant height h apart from the collapse starters (6.sub.2). The shape of the fold starters (6.sub.2) can be defined as follows. In the plan view of FIGS. 1C&1D (variant), they are respectively curved and circumflex, with an outwardly projecting apex. Each starter (6.sub.2) has a midplane of symmetry (66) that includes the axis (64) of the bottle (1). The midplanes 66 of two consecutive collapse starters in the same groove (6.sub.1) form an angle between them of 2.Math.π/n, where n is the number of collapse starters (6.sub.2) per groove (6.sub.1). The angular extent ε of each collapse starter (6.sub.2) about the bottle axis (64) lies in the range about 0.2 radians to 2.Math.π/n; in its midplane of symmetry (66) that includes the axis of the bottle, each collapse starter (6.sub.2) is defined by a generator line or ridge line (68) which extends between the two branches (58) of the groove (6.sub.2) and which is connected to one of said branches by a circular arc 70 whose concave side faces towards the outside and has a radius lying in the range about 0.5 mm to the radius of the circular arc that is tangential to the generator line (68) and to the branch (58) of the groove; the generator line or ridge line (68) is a straight line connected to the other flank (58) of the groove via a rounded portion (72) of minimum radius of curvature, the connection line being curved in shape in a plane that is perpendicular to the axis of the bottle; the generator line or ridge line (68) is inclined relative to the longitudinal axis (64) of the bottle (1) by an angle γ lying in the range 0 to about 45°; and the radial extent λ of the collapse starter (6.sub.2) in the midplane (74) of the groove (6.sub.1) is substantially equal to or slightly less than half the maximum height (h) of the groove (6.sub.1). The radial extent λ is the distance between the bottom (56) of the groove (6.sub.1) and the point of intersection between the ridge line (68) and the midplane (74) of the groove (6.sub.1). From one groove (6.sub.1) to the next, the collapse starters (6.sub.2) are offset angularly through an angle equal to n/n, where n is the number of collapse starters (6.sub.2) per groove (6.sub.1). The number n lies typically in the range 3 to 20. n=4 or 6 in the present examples, wherein the ridge lines (68) of the collapse starters (6.sub.2) are also inclined to slope downwards and outwards. However, it is also possible to use an orientation that is symmetrical to that shown about a perpendicular to the axis (64) of the bottle (1).

(25) In the embodiment herein described as non limiting example, the mean wall thickness (T.sub.mean) of the tubular body portion (6) is comprised between 100 and 140 μm

(26) In order to assess the wall thickness, a generatrix G of the thin-walled bottle (1) is graduated from (0) to (440).

(27) The origin (0) is placed at the center of the bulge (9).

(28) The graduation (440) is placed at the end of the shoulder (5) and at the beginning of the neck (4).

(29) The tubular body portion (6) is comprised between the graduations circa 100 mm and circa 300 mm.

(30) FIG. 3 shows the wall thickness along the generatrix G for a bottle according to the present embodiment and made from PET W170, the intrinsic viscosity of which is circa 0.74 dl/g.

(31) The integral bottom structure (7)

(32) The retractation starter (7.sub.1) joining the terminal curved portion (8) to the bulge is an annular groove or a folding line shown in details on the FIG. 2. Said annular groove (7.sub.1) makes it possible the retractation of the bulge (9), when a upward force is applied on the bottom (7) and/or a downward force is applied on the neck end (2) of the thin-walled bottle (1), as this latter rests on a flat support. This is what is shown on FIGS. 2, 5C, and also on the FIGS. 6A & 6C corresponding to the stacking.

(33) The width of the groove (7.sub.1) is, for instance, comprised between 1-15 mm, preferably between 2-8 mm, more preferably equal to circa 4 mm.

(34) The height of the groove (7.sub.1) is, for instance, comprised between 0.1-10 mm, preferably between 0.5-4 mm, more preferably equal to circa 2 mm.

(35) The center of the bulge (9) comprises an inwardly extended dome (10).

(36) FIG. 4 represent a moulded plastic preform (11) for the blow molding manufacture of the thin-walled bottle (1) as above described. Said preform (11) includes from the top to the bottom: a neck end (20) which is threaded and intended to cooperate with a screw cap; a neck support ring (30); a transition zone (40) which will form the neck (4) of the bottle after blow molding; and a closed tubular body portion (50).

(37) The neck end (20) and the neck support ring (30) foam together the neck finish.

(38) The ratio between the minimum external diameter (D.sub.tz) of the transition zone (40) on the maximum external diameter (D.sub.tb) of the closed tubular body portion (50) is for instance:

(39) D.sub.tz/D.sub.tb is between 1.8 and 0.3, preferably between 1.4 and 0.5 mm, more preferably for instance equal to 36.5/39.5=0.92.

(40) Advantageously the wall thicknesses of the preform (11) is between 1 and 10 mm, preferably between 2 and 7 mm, more preferably for instance equal to 3.25 mm.

(41) Advantageously the ratio weight (g) of the preform (11)/capacity (liters) of the bottle (1), is between 1 and 10, preferably 4 and 7, for instance equal to 5.5.

(42) The blow moulding manufacturing method of the thin-walled bottle/jug (1) as defined above can be illustrated by the example as follows.

(43) 20 liters bottles (1) as above defined are manufactured by injection and blowing with a a standard blow molding device including a shell mold in aluminium with an IR oven composed of 3 ovens and a shaft.

(44) The thermoplastic raw material is a PET resin W170 of NOVAPET and a PET resin Xtreme of VORIDIAN. The intrinsic viscosity of these PET (IV)=0.74 dl/g.

(45) Heat conditioning and preblow step B are implemented. The parameters of this example are given hereafter:

(46) Blowing parameters: Power of the ovens %

(47) TABLE-US-00001 oven 1 oven 2 oven 3 0% 75% 100%  0% 0% 0% 0% 55% 45%  0% 0% 0% 0% 45% 50%  0% 0% 0% 0% 45% 50%  0% 5% 5% 0% 45% 42.5%   0% 0% 0% diameter of the shaft: 16 mm speed: 1.9 m/s flow control: 22% For the blowing: opening 150 mm/closing: 362 mm

(48) The dimensions of the preform and the bottles are as follows:

(49) TABLE-US-00002 Preform Thin-walled bottle (injection step A) (blowing step C) Mean Diameter (mm) 35.65 209 Height without neck 112 350 finish (mm) Total weight (g) 55.43 55.43 Neck weight (g) 4.48 4.48 Body weight (g) 50.95 50.95

(50) The bottles have a good appearance after blowing

(51) The thickness distribution (T.sub.mean) of the bottles is given on FIG. 3

(52) The stretching ratios of the thin-walled bottle (1) of the example are as follows: hoop stretch ratio: 209/35.65=5.86 axial stretch ratio: 3.95 overall stretch ratio: 23.15

(53) The method of bottling a liquid into the of the thin-walled bottle (1) as defined above, consists in filling the thin-walled bottle (1) with a liquid (e.g water) on bottling line, wherein the thin-walled bottle is put under pressure by means of the filled liquid (e.g water) which gives to the thin-walled bottle (1) a mechanical holding/resistance to deformation.

(54) Conventional bottling lines can be adapted to this bottling method.

(55) The method for packing in view of storage and transportation of the thin-walled bottles (1) as defined above, essentially consists in taking advantage of the fact that the upper part of the shoulder (5) together with the neck (4) and the neck finish and the lower part of the integral bottom structure (7) of the thin-walled bottle (1), are retractable under the effect of coaxial forces.

(56) Therefore, it possible to pile the water-filled bottles (1), closed with screwed caps (2′), which are resistant to deformation and which have a self mechanical holding, on top of each other on several levels (100), on a pallet (110).

(57) FIGS. 6A-6B-6C show how the bottles (1) are placed side by side on different superposed levels (100), between which a plate (120) is intercalated. At least some of the bottles' rows are strapped with bands (130). And if need be (see FIG. 6C), an axial pressure is exerted on the top of the top row so as to retract the tops and/or the bottoms of at least some of the palletized thin-walled bottles (1).

(58) The plates (120) can be possibly pierced of holes which are intended to leave the bottles' necks of the lower go through.

(59) It must be emphasized that the remarkable features of the bottles (1) enable a new and efficient way of storage of these bottles (1). Such storage is compact and optimized in terms of transportation.

(60) The method for dispensing a liquid contained in the thin-walled bottle (1) as defined above, as well as the dispenser are described hereinafter in reference to the FIGS. 5A-5J.

(61) The dispenser (500) shown on FIG. 5A comprises a base (510) including in its top a seating (520) designed to receive the top part [neck end (2)-neck support ring (3)-neck (4)-shoulder (5)] of the thin-walled bottle (1), which is set up-side down.

(62) The cap (2′) of the bottle (1) is classically perforated by a tip (not shown) which is connected to an inlet pipe (not shown), which is linked to one or several outlets, by which the liquid (e.g. water) coming from the thin-walled bottle (1) can be dispensed. The outlets are each equipped with valves (530) for controlling the flowing of the liquid (e.g. water).

(63) The setting of the filled bottle (1) up-side down on the seating (520) of the dispenser (500) concomitantly with the perforation the cap (2′) of the bottle (1) is the first step of the method for dispensing the liquid (e.g. water).

(64) It is noteworthy that this first step does not involve entering of ambient air which could have contaminated the liquid (e.g. water). Moreover, the bottle (1) set up-side down keeps its mechanical holding (self supporting) and self collapses as the liquid (e.g. water) is sampled from the dispenser (500) by opening of the valve (530) as shown on FIG. 5A.

(65) The closing of this valve (530) stops the sampling of liquid (e.g. water) as well as the self collapsing of the bottle (1).

(66) The emptying and the self collapsing of the bottle (1) occur till said bottle is (almost) empty and entirely self collapsed. In this state, the bottle (1) forms a waste which not cumbersome (see FIG. 5J) and which can be easily transported and recovered.

(67) The dispenser (500) is a Home Office Dispenser (HOD) which can be equipped either with a manual pump or to an electric pump, and/or with means for refrigerating the water, one of the valve (530) dispensing refrigerated water and the other non-refrigerated water.